if you see latencies on your desktop (such as audio skipping), and suspect
the scheduler, then you can debug them the following way:
1) if possible and relevant, try to make sure you can reproduce the
problem on the sched-devel/latest tree as well:
http://people.redhat.com/mingo/sched-devel.git/README
2) try to do the test on a kernel that has CONFIG_SCHED_DEBUG=y and
CONFIG_SCHEDSTATS=y enabled in its .config. (these options improve
the quality of scheduler instrumentation)
3) run this script to clear all scheduler statistics:
http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info-clear.sh
then reproduce the latency (audio skipping, etc.) on your desktop and
run this script to gather statistics:
http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh
[ take your time to reproduce the problem, then only run the script,
once the problem has occured. Hopefully the incident will be
reflected in the stats. ]
4) send us the file it generates.
[ 5) ] ... optionally, a much more detailed trace of such incidents can
be made using ftrace, see:
http://people.redhat.com/mingo/sched-devel.git/howto-trace-latencies.txt
Ingo